Austin CNC Processing Guide

Most parts do not need five axes. A bracket with holes on one face, a plate with a pocket, or a simple turned bushing runs faster and cheaper on a 3-axis mill or a lathe. Reach for simultaneous 5-axis work when the part has features on multiple faces that cannot be reached in two setups, or when a single setup improves position accuracy between features.

The deciding factor is usually feature access, not part complexity. Count the faces that carry toleranced features. One face: 3-axis. Two to four faces around a rotation axis: 4-axis with a rotary table. Features on five or more faces, or angled bores that must stay true to a datum: 5-axis. Undercuts and deep cavities often push the same decision toward five axes.

Where a 5-axis machine earns its cost is position error. Every extra setup adds a re-clamp tolerance stack. On a part with a true position callout of 0.05 mm between two features on opposite faces, a single 5-axis setup removes that stack entirely. On a part with one toleranced face, that advantage does not exist and you are paying for capability you will not use.

GreatLight runs 16 simultaneous 5-axis machining centers, 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers across three wholly-owned plants covering 7,600 m². Maximum processing size is 4,000 mm, with common travels of 750 × 1,150 × 550 mm and 600 × 600 × 600 mm on medium frames, and 500 × 500 × 450 mm or 500 × 310 × 200 mm on compact frames.

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  One toleranced face3-axis mill, lowest hourly rate
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  Two to four faces around an axis4-axis with Ø400 mm rotary table
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  Five-plus faces or angled boresSimultaneous 5-axis, single setup
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  Turned features plus millingMill-turn center avoids a second operation

Aluminium is the default for most Austin CNC processing work: 6061 and 6061-T6 for general parts, 7075 when strength matters, 2024 when fatigue life does, and 5083 or 6082 for welded and marine assemblies. It cuts fast, holds tight tolerances without much effort, and takes anodizing predictably. If a part has no temperature or wear requirement, aluminium is usually the right first answer.

Stainless is where cycle time climbs. Grades 303 and 304 machine cleanly; 316 and 316L resist corrosion better but work-harden, so light radial passes and constant feed are needed. Grade 17-4PH (SUS630) adds strength after heat treatment, which means machining allowance has to be planned before the heat cycle, not after. Plan the sequence early or the second operation will be a rescue job.

Steel and titanium behave differently again. Grades 1018 and 1045 are straightforward; 4130, 4140 and 4340 are common in shafts and structural parts; A36 and tool steel show up in fixtures. Titanium TA1, TA2 and TC4 (Ti-6Al-4V) need sharp tooling, low cutting speed and good coolant flow because heat stays in the cut. Inconel is slower still. Budget for it in both time and tool wear.

Plastics and composites round out the list. ABS, PC, PMMA, POM, PA, PEEK, PP and HDPE all machine well with the right feeds; PEEK and carbon fibre are abrasive and shorten tool life. Copper and brass, including C36000 and beryllium copper, cut freely but move with temperature, so measurement needs to happen at a stable temperature if the tolerance is tight.

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  Aluminium 6061 / 7075Fast, stable, anodizes well
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  Stainless 304 / 316LWork-hardens; keep the tool moving
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  17-4PHPlan allowance before heat treatment
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  Ti-6Al-4V, InconelSlow speeds, high heat, shorter tool life

A machined surface is not one surface. As-machined at Ra 1.6–3.2 μm is fine for brackets and internal parts. Sealing faces and sliding surfaces usually need Ra 0.8–1.6 μm. Anything below Ra 0.8 μm adds polishing or fine passes and should be justified by function, not by habit. Specifying it everywhere doubles cost on a part that only needs it in two places.

Anodizing comes in clear, colour, hardcoat and conductive variants. Clear and colour are cosmetic and mildly protective. Hardcoat builds a thicker oxide layer for wear resistance, and it grows the part slightly, so mask or compensate dimensions near tight fits. Conductive anodizing keeps electrical contact, which matters on housings that double as a ground path.

Plating options include electroless nickel, zinc, silver and gold. Powder coating and black oxide cover larger cosmetic and corrosion needs. Bead blasting, tumbling, brushing and polishing change the texture before or after coating. Laser marking and engraving put part numbers and lot codes on the surface, with a minimum character height of 1.5 mm so the mark survives handling and stays readable.

The order of operations matters. Mark after coating if the mark must be visible on the final surface. Machine after heat treatment if the tolerance is tight. Decide these two things before the first cut, and most finishing problems disappear before they start.

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  Ra 1.6–3.2 μmAs-machined, fine for internal parts
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  Hardcoat anodizingBuilds thickness; compensate tight fits
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  Conductive anodizingKeeps a ground path through the housing
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  Laser markingMinimum character height 1.5 mm

Inspection here is not a final step, it is three steps. Incoming material is checked against the certificate before it is loaded. Dimensions are monitored during the run, not only at the end, so a drifting tool offset is caught while there is still material to correct. The final inspection covers 100% of parts before shipment, and reports are available on request.

Tolerance claims only mean something with a stated method. A ±0.005 mm callout needs a controlled temperature, a calibrated machine and a measuring tool with resolution well below the tolerance. For most parts that means a CMM or a vision system, not calipers. If your drawing has a true position or profile callout, ask which instrument measures it and how the result is recorded.

Certifications cover the systems behind the work: ISO 9001:2015 for quality management, IATF 16949:2016 for automotive, ISO 13485:2016 for medical devices and ISO 27001:2022 for information security. They do not by themselves make a part good, but they mean traceability, calibration records and corrective action exist when something goes wrong.

The qualification rate on shipped lots is 99.99%. Read that as a rate, not a promise about your specific part. The features that fail are usually the ones with the least clearance and the most ambiguous callouts. Fix the drawing ambiguity and the rate improves for your part too.

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  IncomingMaterial certificate checked before loading
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  In-processDimensions monitored during the run
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  Final100% inspection before shipment
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  ReportsAvailable on request, per lot

A quote is only as good as the file behind it. Send a STEP or IGES model plus a 2D drawing with tolerances, datums, thread callouts and finish requirements. If there is no drawing, the model alone leaves every tolerance to guesswork, and the shop will either quote wide or ask questions. A PDF marked with the critical dimensions answers most of it in one pass.

State the quantity and the target. One prototype and a 500-piece run follow different routes: a prototype may be machined from billet with no fixture, while a run of 500 usually justifies a soft jaw or a fixture to cut cycle time. Quantity also decides whether die casting, vacuum casting or sheet metal is cheaper than machining for the same geometry.

Material, finish and inspection level each move the number. So does the tolerance band. If only three dimensions need ±0.005 mm and the rest can sit at ±0.1 mm, say so. That single sentence can cut cycle time more than any negotiation. We return a quotation and a free DFM analysis within 12 hours, and production can start within 24 hours.

Uploads are kept secure and confidential. An NDA is available on request, and no minimum order quantity applies, so a single prototype and a 10,000-part run go through the same quoting process. Parts typically ship in 3–5 days; the historical late-delivery probability is below 2%.

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  SendSTEP model plus 2D drawing with datums
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  StateQuantity, material, finish, inspection level
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  SeparateCritical tolerances from general ones
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  AvoidUnilateral tolerances on non-functional features